Sure it was hot - but 9 degrees diff on a RA-1?

[JeremyD]

Between cold (relative) and after a session.

started at 31 and was at 40 at the end of a session - 2nd session started at 28 and went to 37. It's my first time with RA-1's

The cold temp in the pits
[img]http://forums.pelicanparts.com/uploads8/hot*****1150254233.jpg[/img]

They were pretty uniform 145 degrees across after the first session 155 degrees the 2nd.

is this normal?

[JeremyD]

it was 97 degrees in the shade...

[nostatic]

On hot days I've seen my RA-1s jump like that. I generally don't measure cold though. I try to run about 32 front 34 rear hot. Some say that is too low, but much higher and they feel a bit wallowing to me.

[earlyapex]

Yes.

[Tyson Schmidt]

Perfectly normal, perfectly healthy.


If you don't see that kind of spread, you aren't driving hard enough.


BTW, cold pressures are irrelevant. Hot pressure at the track are all that matter.

[JeremyD]

OK - thanks guys....

[Ducman]

Looks good to me

I generally start 32/34 f/r cold targeting 42/42 hot

[juanbenae]

jd/others were those shaved? i just got a set of foo tread depth ra-1 and was looking for starting cold pressure to develope my base line starting points.

given that, what is an ideal hot pressure with a 2800lbs car? is the 32/34 listed above a good place to start? thunder hill in a week, so i am hoping for 85*-90* air temps late in the day. it does not hurt to dream does it? 85-90 in late june there....

please advise?

T$

[Jim Richards]

+1

[JeremyD]

I scuffed all the way to the edge of the tire = but not over the "corner" so think the pressures are ok for my car = hot 35/37

My car is around 2800 lbs.

[Chuck Moreland]

Originally posted by JeremyD
They were pretty uniform 145 degrees across after the first session 155 degrees the 2nd.

Assuming you are getting your temps before the tires start to cool, you really need to get more heat into the tires. Get into the 180-190 range and they will really start to hook up.

You can do this be driving harder, or reducing pressure.

[JeremyD]

not really - cool down lap - trip back to the paddock - ho hum - check the temp... Thanks though Chuck -

[Tom W]

When my car was 2800 lbs I aimed for 36/38 hot with RA-1s but i never got too much experience with them (mostly MPSCs). The best way to determine what pressure works best is try something else. Do your lap times decrease? It's better. Are they slower? It's not.

[juanbenae]

Originally posted by Tom W
The best way to determine what pressure works best is try something else. Do your lap times decrease? It's better. Are they slower? It's not.

i am not consistent enough at this point to have lap times reveal much. plus, at DE's you have the traffic issue at times that will not allow for real good tracking.

i had my victoracers to where i could set them up early and only check them after lunch when the temps increased. the last day out with them right before they corded was amazing. the grip was unreal and i felt very confident in them. back to the drawing board now??

T$